根据MySql文档,我们知道在修改表内某一列的属性的时候,MySql支持3中语法结构: ALTER [ONLINE|OFFLINE] [IGNORE] TABLE tbl_name ALTER [COLUMN] col_name {SET DEFAULT literal | DROP DEFAULT} ALTER [ONLINE|OFFLINE] [IGNORE] TABLE tbl_name CHANGE [COLUMN] old_col_name new_col_name column_definition [FIRST|AFTER col_name] ALTER